This invention relates generally to percutaneous electrical therapy systems for medical use. In particular, the invention relates to an electrode assembly for inserting, using and removing percutaneous electrodes.
Electrical therapy has long been used in medicine to treat pain and other conditions. For example, transcutaneous electrical nerve stimulation (TENS) systems deliver electrical energy through electrode patches placed on the surface of a patient""s skin to treat pain in tissue beneath and around the location of the patches. The efficacy of TENS systems in alleviating pain is questionable at best, however.
More recently, a technique in which electrodes are placed through the patient""s skin into the target tissue has been proposed. Percutaneous Neuromodulation Therapy (xe2x80x9cPNTxe2x80x9d) (also sometimes called Percutaneous Electrical Nerve Stimulation or xe2x80x9cPENSxe2x80x9d) using percutaneously placed electrodes achieves significantly better pain relief results than TENS treatments using skin surface electrodes. This therapy is described in Ghoname et al., xe2x80x9cPercutaneous Electrical Nerve Stimulation for Low Back Pain,xe2x80x9d JAMA 281:818-23 (1999); Ghoname et al., xe2x80x9cThe Effect of Stimulus Frequency on the Analgesic Response to Percutaneous Electrical Nerve Stimulation in Patients with Chronic Low Back Pain,xe2x80x9d Anesth. Analg. 88:841-6 (1999); Ahmed et al., xe2x80x9cPercutaneous Electrical Nerve Stimulation (PENS): A Complementary Therapy for the Management of Pain Secondary to Bony Metastasis,xe2x80x9d Clinical Journal of Pain 14:320-3 (1998); and Ahmed et al., xe2x80x9cPercutaneous Electrical Nerve Stimulation: An Alternative to Antiviral Drugs for Herpes Zoster,xe2x80x9d Anesth. Analg. 87:911-4 (1998). The contents of these references are incorporated herein by reference.
Thus far, PNT practitioners have used percutaneously placed acupuncture needles attached to waveform generators via cables and alligator clips to deliver the therapy to the patient. This arrangement and design of electrodes and generator is far from optimal. For example, insertion and removal of percutaneous electrodes has thus far been cumbersome and inaccurate. In addition, the prior art has not adequately addressed the issue of sharps protection for the patients"" caregivers and other bystanders. It is therefore an object of this invention to reduce the exposure of electrical therapy patients"" caregivers to accidental exposure to bloodborne pathogens, microbes, toxins, etc., via an injury caused by unintended contact with a sharp electrode.
It is a further object of this invention to provide a percutaneous electrical therapy system having electrodes and electrode assemblies that are safe, efficacious, inexpensive and easy to use.
Other objects of the invention will be apparent from the description of the preferred embodiments.
The invention is a percutaneous electrode assembly. In a preferred embodiment, the assembly includes a housing adapted to be mounted on a patient; an electrode disposed in the housing, the electrode having an sharp point at a distal end adapted to be inserted into a patient""s tissue; an electrode actuator disposed in the housing and adapted to move the sharp point of the electrode out of the housing; and an electrode electrical connector adapted to electrically connect the electrode to a control unit to deliver electrical therapy to a patient.
In one embodiment, the assembly also includes a limit stop limiting movement of the electrode out of the housing.
The assembly may also include an actuator tool adapted to engage the actuator to move the sharp point of the electrode out of the housing. The actuator tool may have a conductor adapted to electrically communicate with the electrode electrical connector.
The invention is also a method of inserting a percutaneous electrode into a patient. In a preferred embodiment, the method includes the following steps: placing a housing on a patient; and moving at least part of an electrode out of the housing and into the patient and connecting the electrode electrically with a control unit cable, the moving and connecting steps being performed with a single user motion.
In some embodiments, the placing step includes the step of attaching the housing to the patient, such as with adhesive.
In some embodiments, the moving and connecting steps include engaging a tool to move at least a portion of the electrode out of the housing and to connect the electrode electrically with the control unit cable. If the method also includes the step of treating the patient with electrical therapy by delivering electricity to the electrode, the tool may remain engaged during treatment.
In some embodiments, the method may include the step of moving the electrode back into the housing and disconnecting the electrode electrically from the control unit cable, the steps of moving the electrode back and disconnecting the electrode being performed with a single user motion.
The invention is described in more detail below with reference to the drawings.